Gas turbine engines are often used in aircraft, among other applications. For example, gas turbine engines used as aircraft main engines may provide propulsion for the aircraft but are also used to provide power generation. Such propulsion systems for aircraft must deliver high performance in a compact, lightweight configuration. This is particularly important in smaller jet propulsion systems typically used in regional and business aviation applications as well as in other turbofan, turboshaft, turboprop and rotorcraft applications. A well-known way to improve engine efficiency is to increase the overall pressure rise of the compressor.
The airfoil blade loadings or stage counts for the fan (i.e. low pressure compressor) and high-pressure compressor may be increased for increasing cycle pressure ratios (Poutlet/Pinlet) to improve turbine engine performance. Increasing stage count has a detrimental impact on engine length, weigh and cost. Increasing airfoil loading (with increased pressure rise in each stage) has a tendency to reduce the compressor surge margin and stability margin such that the compressor must be operated away from a near stall condition, thereby reducing efficiency potential using conventional engine design technology. However, the reduced surge margin and lower efficiency potential can cause engine instability, increased specific fuel consumption and increased turbine operating temperatures in both steady state and transient operation.
Accordingly, there is a need for an improved compressor configuration that achieves the required surge and stability margins and maintains the efficiency potential of the turbine engine. There is also a need for an improved gas turbine engine with an improved compressor configuration that achieves the required surge and stability margins and maintains the efficiency potential of the turbine engine. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.